High Speed Production of Large Coal, to Facilitate Easier and More Effective Cleaning by David A. Summers, Stewart Gillies, Kwame Awuah-Offei, & Greg Galecki Mining and Nuclear Engineering Department Missouri S&T
The United States has four major energy sources One million barrels of oil a day is equivalent to: – 2.08 trillion cubic feet of natural gas a year. – 94 million tons of coal a year – 200 billion kilowatt hours of nuclear power a year. – 203 billion kilowatt hours of hydropower a year – 2.12 Quads (10 15 ) Btu’s per year. The US uses over 20 million barrels of oil a day (Source EIA).
But needs coal to create electricity While coal is the current dominant fuel, because of concerns over carbon dioxide, most recent additions burn natural gas instead. But as it and oil become less available and more expensive coal will dominate. Source EIA 2006 data Oil Other gas Hydro PS
US Coal Production Recently David Rutledge, and others have looked at sources of American coal and are concerned that the resource will start to run out by Source: Hubbert’s Peak, The Coal Question, and Climate Change David Rutledge, Caltech web: rutledge.caltech.edu
Pennsylvania Anthracite Production By looking at plots such as this for PA Anthracite, they anticipate future declines But the circumstances for these declines have not been because of a lack of resource, rather it has been because of other factors, including costs of production, relative to price elsewhere. 5 Source: Hubbert’s Peak, The Coal Question, and Climate Change David Rutledge, Caltech web: rutledge.caltech.edu
In the past mining machines have not looked to energy production costs, as they were low Most mining machines grind coal from the solid This produces lots of dust, and fine coal, which is neither efficient nor particularly safe.
But earlier machines worked, as manual mining does, by only cutting part of the face The Meco Moore machine used cutting bars to cut at the bottom middle and back of the coal and the remaining coal fell under its own weight and could be loaded onto a conveyor.
The MO S&T Hydro-miner was designed to use waterjets to make the same sort of cuts Oscillating waterjetc cut at the top, bottom and back of the coal to break out a column
Tests of an initial design were carried out on the surface in northern Missouri An initial design was pulled along an exposed coal seam
The jets produced larger coal, faster and with less force
And because of the jet infusion and cutting there is no dust or risk of gas ignition
A second generation machine was built And tested in a test facility in Bruceton by the Bureau of MInes
It worked even in cutting harder simulated coal Though we learned the importance of wedge and clearance angles
It used a dual jet to cut a wider slot
The method was tried underground Tests at the Lohberg mine in Germany showed that the coal was mined fast, and relatively inexpensively. But the world market for the machines at the time was too small.
We tried the same idea in room and pillar
First two stages
We built a prototype But the end of the Energy Crisis meant that we ran out of funding
There are other ways to break the rib
The jets cut ribs that the auger easily breaks
Inside the hole the walls keep the coal in the scroll
And you don’t need a lot of force to move it forward (note the broken arm)
You can then bore out adjacent cuts along a highwall, or underground.
There are many ways of producing coal more easily and from thinner seams remotely. The Mining Industry has not had to look to these ideas yet. When they do they will be able to mine many seams that are now considered unworkable, but which are only, with current technologies uneconomic.
Acknowledgments Dr. Clark Barker Of MS&T initial design Jet Propulsion Laboratory for support and assistance National Aeronautics and Space Administration for program support RMERC staff for field support and system construction U.S. Department of Energy for program support U.S. Department of the Interior for program support National Institute of Standards and Technology for program support